A number of articles and studies are beginning to appear that suggest that many of the clergy are, in fact, atheists. This issue was raised in an AlterNet article, Major Threat to Religion? Clergy People Coming Out as Atheists.
There is a web "safe house" for clergy who are atheists, The Clergy Project, "a safe haven for active and former clergy who do not hold supernatural beliefs".For clergy people, losing religion doesn't just mean asking questions like, "How do I accept the permanence of death?" and "What is my place in the universe?" It means asking the question, "How am I going to pay the rent?" For most clergy members, coming out as atheist means the automatic loss of their livelihood. But staying closeted about their atheism means living a lie. As MacBain said, "Once I realized my faith was gone, I began looking for a way out. My conscience nagged at me continually but I felt that the needs of my family required that I work my way out slowly. I took a temporary job (causing me to work 80 hour weeks) in order to pay some bills off which would make the transition easier. As the weeks passed, the turmoil increased exponentially."
A study by researchers at Tuft University, Preachers who are not Believers, surveyed a number of atheist clergy.
In the early 1970s, I met a Canadian priest working in Lampa, Peru. He was about 75. He and I spent some time traveling in the various regions of Peru. I was making a documentary. He took advantage of my Toyota Land Rover to visit parishes. One night as we drank mugs of Pisco brandy on a dock in Pucallpa, he confided that he had stopped believing in God while in the seminary. He stayed with the Church only because it gave him an opportunity to help people, and make a living doing it. He did say that if he was wrong he didn't think God would judge him too harshly.[The sample is] small and self-selected, and it is not surprising that all of our pastors think that they are the tip of an iceberg, but they are also utterly unable to confirm this belief. They might be deluding themselves, but in any case their isolation from others whom they suspect are in the same boat is a feature they all share, in spite of striking differences in their stories and attitudes. While we couldn’t draw any reliable generalizations from such a small sample of clergy, the very variety of their stories, as well as the patterns discernible in them, suggest fascinating avenues for further research on this all but invisible phenomenon.
I suspect that a very large minority of clergy, in fact, do not believe in God, but they simply have no reasonable way to come out of the religious "closet".